Operando Neutron Characterization During 3D Printing
A new laser powder bed fusion device enables real-time neutron diffraction and imaging, providing detailed insights into structural evolution, defect formation, and temperature mapping during metal additive manufacturing.
YBa1−𝑥Sr𝑥CuFeO5 layered perovskites: An attempt to explore the magnetic order beyond the paramagnetic-collinear-spiral triple point
Layered perovskites of general formula AA'CuFeO5 are characterized by the presence of spiral magnetic phases whose ordering temperatures 𝑇spiral can be tuned far beyond room temperature by introducing modest amounts of Cu/Fe chemical disorder in the crystal structure. This rare property makes these materials prominent candidates to host multiferroicity and magnetoelectric coupling at temperatures suitable for applications. Moreover, it has been proposed that the highest 𝑇spiral value that can be reached in this structural family ( ∼400 K) corresponds to a paramagnetic-collinear-spiral triple point with potential to show exotic physics. Since generating high amounts of Cu/Fe disorder is experimentally difficult, the phase diagram region beyond the triple point has been barely explored. To fill this gap we investigate here eleven YBa1−𝑥Sr𝑥CuFeO5 solid solutions (0≤𝑥≤1 ), where we replace Ba with Sr with the aim of enhancing the impact of the experimentally available Cu/Fe disorder. Using a combination of bulk magnetization measurements, synchrotron x-ray and neutron powder diffraction we show that the spiral state with 𝐤𝑠=(1/2,1/2,1/2±𝑞) is destabilized beyond a critical Sr content, being replaced by a fully antiferromagnetic state with ordering temperature 𝑇coll2≥𝑇spiral and propagation vector 𝐤𝑐2=(1/2,1/2,0). Interestingly, both 𝑇spiral and 𝑇coll2 increase with 𝑥 with comparable rates. This suggests a common, disorder-driven origin for both magnetic phases, consistent with theoretical predictions.
Connection between f-electron correlations and magnetic excitations in UTe2
The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe2 is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic b-axis. In applied magnetic fields ...
Decentralized hydrogen-based stationary energy storage systems complemented by smart control can provide increased operational flexibility in the energy system
While the electrification of the energy system implies a reduction of greenhouse gas emissions greatly beneficial to society, it can also pose technical challenges. The most notable among these are that the capacity of the local electric grid may be exceeded, along with the occurrence of imbalances between decentralized renewable energy production and final consumption. Hydrogen-based energy storage systems (HESS) are regarded as promising solutions to address these challenges. However, the feasibility has not been demonstrated and the involved processes are not well characterized on a technical relevant power level, so far.
Small-angle scattering interferometry with neutron orbital angular momentum states
Methods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) were recently demonstrated at small-angle neutron scattering (SANS) facilities. These methods enable access to the neutron orbital degree of freedom which provides new avenues of exploration in fundamental science experiments as well as in material characterization applications.
However, ....
Mitigating Cracks in Multi-Material Printing
Integrating metallic powders with thin foils in laser powder bed fusion can reduce interfacial cracks and improve microstructure quality in titanium-aluminum multi-material printing.
Fractional quasiparticles in three dimensions
Specific signatures of fractionalization have been observed in a three-dimensional system known as quantum spin ice.
Evidence of antiferromagnetism in ultrathin metallic (111)-oriented LaNiO3 films
Antiferromagnets with exotic spin textures promise low-power spintronic devices with extremely high operating frequencies and resistance to external perturbations. In particular, the combination of highly tunable correlated electron physics, as in complex oxides, with metallicity and antiferromagnetism is desirable but exceedingly rare. LaNiO3, the lone example of a perovskite nickelate which is metallic across all temperatures, has long been a promising candidate, but the antiferromagnetic metallic state has remained elusive. We demonstrate the emergence ...
Not Rocket Science, just Nuclear Rocket Science
The PSI Laboratory for Reactor Physics and Thermal-Hydraulics (LRT) conducts computational and experimental research with focus on the safety of nuclear reactors and systems. In recent years, it established the EPSILON program to coordinate and consolidate its research activities on nuclear space applications. Among other things, developments were initiated towards an open-source European platform for high-fidelity simulations and experiments dedicated to space nuclear reactors. Referred to as the openSPACE platform, its underlying concepts are a) to include not only solvers but also reference simulation models as well as experimental validation data; b) to make all of these available to the broader and combined nuclear- and space communities for usage and/or further developments. Through this, the goal is thus not only to facilitate collaborative research in this area but also to enable effective support to the European Space Agency for thorough design, safety and performance evaluations of nuclear reactor systems for in-space propulsion and/or surface power. A first development phase focused on nuclear electric propulsion was proposed and retained among the two projects selected in 2023 by the Swiss National Science Foundation (SNSF) for its MARVIS call (Multidisciplinary Advanced Research Ventures in Space) and funded by the Swiss Secretariat for Research and Innovation (SERI). This project, to be conducted via four inter-connected PhD theses, was launched in October 2024 and this marks thus a key milestone for the propulsion of PSI nuclear research towards space.
Origin of the Suppression of Magnetic Order in MnSi under Hydrostatic Pressure
We experimentally study the evolution of the magnetic moment 𝑚 and exchange interaction 𝐽 as a function of hydrostatic pressure in the zero-field helimagnetic phase of the strongly correlated electron system MnSi. The suppression of magnetic order at ≈1.5 GPa is shown to arise from the 𝐽 collapse and not from a quantum fluctuations induced reduction of 𝑚. Our work provides benchmarks ...
Understanding the Interplay between Artificial SEI and Electrolyte Additives in Enhancing Silicon Electrode Performance for Li-Ion Batteries
Maintaining a stable solid electrolyte interphase (SEI) is crucial for Li-ion battery safety, especially with high-capacity anode containing silicon. Therefore, our study explored long-term cycling of Si electrodes with artificial alucone-based SEI, deposited by molecular layer deposition (MLD) in combination with a fluoroethylene carbonate (FEC) electrolyte additive. MLD of flexible Li-ion permeable artificial SEI coatings onto electrode resulted in improved capacity, enhanced Si electrode cycle life and capacity retention.
Preparing the Future of PSI Large Facilities in Atmospheric Research
The Multiphase Chemistry Group in the Laboratory of Atmospheric Chemistry (LAC) looks back to a nearly 20 years record of activities with in situ X-ray photoelectron spectroscopy (XPS) and in situ scanning transmission X-ray spectromicroscopy (STXM) to address key fundamental questions in atmospheric chemistry. This is the time to consider new horizons, align with current and future needs in atmospheric sciences, and to identify novel opportunities driven by upcoming trends in methods, technologies and facilities. This has been the topic of the Workshop ‘X-ray and Neutron Spectroscopy, Scattering and Imaging in Atmospheric Chemistry’, held at PSI 13 – 15 November 2024.
Anionic Disorder and Its Impact on the Surface Electronic Structure of Oxynitride Photoactive Semiconductors
The conversion of solar energy into chemical energy, stored in the form of hydrogen, bears enormous potential as a sustainable fuel for powering emerging technologies. Photoactive oxynitrides are promising materials for splitting water into molecular oxygen and hydrogen. However, one of the issues limiting widespread commercial use of oxynitrides is degradation during operation. While recent studies have shown the loss of nitrogen, its relation to reduced efficiency has not been directly and systematically addressed with experiments. In this study, we demonstrate the impact of the anionic stoichiometry of BaTaOxNy on its electronic structure and functional properties. Through experimental ion scattering, electron microscopy, and photoelectron spectroscopy investigations, we determine the anionic composition ranging from the bulk toward the surface of BaTaOxNy thin films. This further serves as input for band structure computations modeling the substitutional disorder of the anion sites. Combining our experimental and computational approaches, we reveal the depth-dependent elemental composition of oxynitride films, resulting in downward band bending and the loss of semiconducting character toward the surface. Extending beyond idealized systems, we demonstrate the relation between the electronic properties of real oxynitride photoanodes and their performance, providing guidelines for engineering highly efficient photoelectrodes and photocatalysts for clean hydrogen production.
Operando phase mapping in multi-material laser powder bed fusion
Additive manufacturing (AM) or “3D printing” of metals, which builds structure layer by layer, has revolutionized the production of intricate 3D designs. Among its techniques, laser powder bed fusion (PBF-LB) excels in creating metallic parts with intricate designs and high precision. This process can combine different metals into innovative multi-material components with tailored properties, with regards to e.g., strength and thermal conductivity, surpassing the capabilities of single-material designs. However, ....
Acoustic emission signature of a martensitic transformation
Acoustic emission monitoring in 3D printing: real-time insights into martensitic phase transformations and crack formation.
Exact solution of the classical and quantum Heisenberg mean field spin glasses
We solve and elucidate the physics of quantum Heisenberg spins glasses, which governs the local moments in randomly doped, strongly correlated materials.
Sample-position tracking using computer vision algorithms
In a collaboration between PSI and the Zurich University of Applied Sciences, a sample position tracking setup based on a computer vision algorithm was developed to automatically track the sample position. A factor of ten improvement on the overlap between consecutive x-ray absorption spectra was obtained when the automatic sample tracking was used.
Continuum Excitations in a Spin Supersolid on a Triangular Lattice
Magnetic, thermodynamic, neutron diffraction and inelastic neutron scattering are used to study spin correlations in the easy-axis XXZ triangular lattice magnet K2Co(SeO3)2. Despite the presence of quasi-2D “supersolid” magnetic order, the low-energy excitation spectrum contains no sharp modes and is instead a broad and structured multiparticle continuum. Applying a weak magnetic field ...
Best practices for harnessing operando X-ray absorption spectroscopy in electrocatalytic water splitting studies
X-ray absorption spectroscopy (XAS) has found applications in a range of fields including materials, physics, chemistry, biology and earth science. XAS can probe the local electronic and geometric structure, such as the average oxidation state, coordination environment and interatomic distances, surrounding an element of interest. Thus, XAS is a valuable tool to inform catalyst design by tracking catalyst evolution under operating conditions, for example, via providing dynamic snapshots of the essential information.
Reentrant multiple-q magnetic order and a “spin meta-cholesteric” phase in Sr3Fe2O7
Topologically nontrivial magnetic structures such as skyrmion lattices are well known in materials lacking lattice inversion symmetry, where antisymmetric exchange interactions are allowed. Only recently, topological multi-q magnetic textures that spontaneously break the chiral symmetry, for example, three-dimensional hedgehog lattices, were discovered in centrosymmetric compounds, where they are instead driven by frustrated interactions. Here we show that ...
Skyrmion topology quantified in 3D
Researchers from an international collaboration between the United States of America and Switzerland have performed three-dimensional magnetic imaging of a magnetic skyrmion using soft X-ray laminography. This allowed for the investigation, in three dimensions, of the topological profile of the magnetic skyrmions.
Dual-site reaction mechanism for the simultaneous reduction of nitrous and nitric oxides
We have applied three spectroscopic techniques (XAS, EPR and DRIFTS) in combination withe modulated excitation and catalytic data to decipher and propose the complete reaction mechanism of the simultaneous reduction of N2O and NO
Discovery of charge order above roomtemperature in the prototypical kagome superconductor La(Ru1−xFex)3Si2
The kagome lattice is an intriguing and rich platform for discovering, tuning and understanding the diverse phases of quantum matter, crucial for advancing modern and future electronics. Despite considerable efforts, accessing correlated phases at room temperature has been challenging.
Recognition at MNE 2024 Micrograph Contest
The MNE conference is the flagship event of the International Society for Micro- and Nanotechnology (iMNEs). The research fields covered by the MNE conferences have consistently driven advancements in the development of smaller and smaller structures. To emphasize the significance of micrographs in this field, the conference features a micrograph contest, sponsored and hosted by Zyvex Labs. Entries are judged based on both their technological relevance and artistic merit.
This year, Peng Qi from the X-ray Nano Optics group, LXN, CPS, earned third place and an honorable mention for his two submitted images.
Converting the CHF3 greenhouse gas into LiF coating for high-voltage cathode materials toward high-energy density Li-ion batteries
The instability and the fading of high voltage cathode materials above 4.3 V remains a major challenge for the next generation of high energy density Li-ion batteries. Here, we present a facile, environmentally friendly, cost effective and scalable method to address this problem by uniformly fluorinating the surface of cathode materials with CHF3, a mild fluorinating agent but a potent greenhouse gas. CHF3 is successfully transformed into ~2 nm LiF homogenous layer covering the surface of layered-oxide cathode materials.
Ferromagnetic quantum critical point protected by nonsymmorphic symmetry in a Kondo metal
Quantum critical points (QCPs), zero-temperature phase transitions, are win- dows to fundamental quantum-mechanical phenomena associated with universal behaviour. Magnetic QCPs have been extensively investigated in the vicinity of antiferromagnetic order. However, QCPs are rare in metallic ferromagnets due to the coupling of the order parameter to electronic soft modes. Recently, antisymmetric spin-orbit coupling in noncentrosymmetric systems was suggested to protect ferromagnetic QCPs. Nonetheless, multiple centrosymmetric materials ...
Uncovering the secrets of rapid and green metal-organic framework synthesis
Using ATR-IR spectroscopy and high-energy XRD, we have studied the mechanism of ambient temperature aqueous synthesis of Zn-MOF-74. Starting from the need to change Zn precursor to disentangle signals in ATR-IR spectroscopy, we also developed a rapid synthesis of Zn-MOF-74 with Zn perchlorate.
Carbenium ions in the methanol-to-olefins process
The methanol-to-olefins process converts methanol into hydrocarbons over zeolite-based catalysts following a dual-cycle reaction mechanism within the paradigm of an hydrocarbon pool chemistry. In this work, we use operando DRIFTS/GC to correlate the nature of species residing within the porosity of zeolites (DRIFTS) and the products distribution (GC).
Quantum Spin Dynamics Due to Strong Kitaev Interactions in the Triangular-Lattice Antiferromagnet CsCeSe2
The extraordinary properties of the Kitaev model have motivated an intense search for new physics in materials that combine geometrical and bond frustration. In this Letter, we employ inelastic neutron scattering, spin wave theory, and exact diagonalization to study the spin dynamics in the perfect triangular-lattice antiferromagnet (TLAF) CsCeSe2. This material orders into a stripe phase, which is demonstrated to arise as a consequence of the off-diagonal bond-dependent terms in the spin Hamiltonian ...
Evidence for time-reversal symmetry-breaking kagome superconductivity
Superconductivity and magnetism are often antagonistic in quantum matter, although their intertwining has long been considered in frustrated-lattice systems. Here we utilize scanning tunnelling microscopy and muon spin resonance to demonstrate time-reversal symmetry-breaking superconductivity in kagome metal Cs(V, Ta)3Sb5, where the Cooper pairing exhibits magnetism and is modulated by it. In the magnetic channel, we observe spontaneous internal magnetism ...
Hydrogen Electrode for Membrane Water Electrolyzers with Low Gas Crossover
Proton exchange membrane (PEM) water electrolyzer are considered a for the Energy Transition to produce green hydrogen for fuel cell-based mobility, industrial processes, and seasonal storage. Platinum group metals (PGMs) are conventionally used as catalysts for electrode reactions due to their outstanding catalytic activity and chemical stability in the harsh acidic environment of the cell. Commercial carbon-supported platinum (Pt/C) electrocatalysts remains a state-of-the-art choice for the hydrogen evolution reaction (HER) on the cathode side of the cell. While a high Pt loading between 0.5 and 1.0 mgPt/cm2 is commonly used today, a reduction of the Pt loading to below 0.05 mgPt/cm2 is desired to reduce the cost of PGM usage in megawatt-scale PEM water electrolysis systems. In addition, in connection with the trend towards the use of thinner membranes (<0.1 mm), gas crossover through the membrane from the cathode to the anode side can lead to the formation of an explosive gas mixture in the anode product stream. In this study, we varied the design parameters for the cathode catalyst layer to reduce the Pt loading to 0.025 mg/cm2 while at the same time minimizing the rate of hydrogen crossover to the anode.
Controlling magnetic waves in a spin liquid
Scientists at the Paul Scherrer Institute PSI have shown that excitation of a spin liquid with intense THz pulses causes spins to appear and align within less than a picosecond. This induced coherent state causes a magnetic field to form inside the material, which is detected using ultrashort X-ray pulses at the X-ray Free Electron Laser SwissFEL.
Novel Photoresist Chemistry Enables Lithography Approaching Angstrom-Scale Resolution
Photoresist materials are crucial in the manufacturing of computer chips, where the circuits are initially printed in the photoresist using photolithography. As the demand for smaller and more precise circuitry in computer chips grows, photoresists must resolve features with smaller sizes and higher density. One of the factors determining the ultimate resolution in lithography is the molecular size/mass of the photoresists.
Chiral kagome superconductivity modulations with residual Fermi arcs
Superconductivity involving finite-momentum pairing can lead to spatial-gap and pair-density modulations, as well as Bogoliubov Fermi states within the superconducting gap. However, the experimental realization of their intertwined relations has been challenging. Here we detect chiral kagome superconductivity modulations with residual Fermi arcs in KV3Sb5 and CsV3Sb5 using normal and Josephson scanning tunnelling microscopy down to 30 millikelvin with a resolved electronic energy difference at the microelectronvolt level. We observe a U-shaped ...
Room temperature magnetoelectric magnetic spirals by design
Frustrated magnets with ordered magnetic spiral phases that spontaneously break inversion symmetry have received significant attention from both fundamental and applied sciences communities due to the experimental demonstration that some of these materials can couple to the lattice and induce electric polarization. In these materials, the common origin of the electric and magnetic orders guarantees substantial coupling between them, which is highly desirable for applications ...
Magnetostructural Coupling at the Néel Point in YNiO3 Single Crystals
The recent discovery of superconductivity in infinite layer thin films and bulk Ruddlesden–Popper nickelates has stimulated the investigation of other predicted properties of these materials. Among them, the existence of magnetism-driven ferroelectricity in the parent compounds RNiO3 (R = 4f lanthanide and Y) at the onset of the Néel order, TN, has remained particularly elusive. Using diffraction techniques, we reveal here the existence of magnetostriction at TN in bulk YNiO3 single crystals. Interestingly, the associated lattice anomalies ...
Elusive multiferroicity in RNiO3 perovskites
In our recent paper we examined YNiO3 and proved that the RNiO3 type material known for its metal-insulator transition is in fact a type II multiferroic. We provide direct evidence of an electric-field-driven switch of the noncolliear magnetic state finally confirming the proposed type II multiferroic nature of YNiO3.
Move the soft mode by electric fields in quantum paraelectric SrTiO3
PSI Researcher used inelastic neutron scattering to show how collective lattice vibrations can be controlled by electric fields. These results indicate that different eigenmodes can couple in field in this incipient ferroelectric.
Move the soft mode by electric fields in quantum paraelectric SrTiO3
PSI Researcher used inelastic neutron scattering to show how collective lattice vibrations can be controlled by electric fields. These results indicate that different eigenmodes can couple in field in this incipient ferroelectric.
Conventional superconductivity in the doped kagome superconductor Cs(V0.86Ta0.14)3Sb5 from vortex lattice studies
A hallmark of unconventional superconductors is a complex electronic phase diagram where intertwined orders of charge-spin-lattice degrees of freedom compete and coexist. While the kagome metals such as CsV3Sb5 also exhibit complex behavior, involving coexisting charge density wave order and superconductivity, much is unclear about the microscopic origin of the superconducting pairing. We study the vortex lattice in the superconducting state of Cs(V0.86Ta0.14)3Sb5, where the Ta-doping suppresses charge order and enhances superconductivity. Using small-angle neutron scattering ...
Nanoimaging Reveals Topological Textures in Nanoscale Crystalline Networks
X-ray nano-tomography reveals collective behavior in synthetic self-assembled nanostructures. The new method opens opportunities for the synthesis of photonic and plasmonic materials with improved long-range ordering.
Installation of the first two front ends for the SLS2.0 completed
At the Swiss Light Source SLS of the Paul Scherrer Institute, another important step has been taken towards the completion of the SLS 2.0 upgrade project.
Insights into the superior oxygen evolution reaction activity of CoOx/CeO2 composite electrocatalyst
CeO2 significantly enhances the oxygen evolution reaction (OER) activity of CoOx, although the mechanism behind this synergy is still unclear. Here, operando hard X-ray absorption spectroscopy (hXAS) is applied to monitor the Co-K edge and Ce L3 edge in CoOx/CeO2 to shed light on the evolution of Co and Ce oxidation states during OER. In addition, ex situ soft XAS (sXAS) characterizations provide information on the irreversible surface-specific transformations of the Co L3 edge as well as the O K edge.
Real-Time Insights into Sodium-Ion Battery Chemistry
Identification of gaseous decomposition products from irreversible side-reactions enables understanding of inner working of rechargeable batteries. Unlike for Li-ion batteries, the knowledge of the gas-evolution processes in Na-ion batteries is limited. Our study revealed that Na-ion cells develop a less stable solid-electrolyte interphase (SEI) compared to Li-ion cells due to higher solubility of SEI constituents in Na-electrolytes.
Anomalous spin precession systematic effects in the search for a muon EDM using the frozen-spin technique
In the paper, the international muEDM collaboration at PSI discusses systematic effects of the most sensitive measurement of the muon's electric dipole moment (EDM). Scientists from Europe are developing a prototype experiment using the frozen-spin technique (FST) to achieve unprecedented sensitivity. The FST meticulously aligns a magnetic field with a perpendicular electric field so that the muon's spin orientation always follows its momentum. This enhances the sensitivity to the muon EDM by about 3 orders of magnitude compared to the best result from the muon g-2 experiment at Brookhaven National Lab.
The paper addresses systematic effects that could mimic an EDM signal when E- and B-fields are not perfectly aligned, adjusted, or stable over time. While most effects cancel out when reversing the magnetic field, some residual effects the specifications for the fields' uniformity, stability, and orientation,
which are challenging but achievable.
Removal of ionic and colloidal 110 mAg from radioactive wastewater using radiografted chelating adsorbents
Nuclear power plays a crucial role in a sustainable future due to its ability to generate large amounts of low-carbon electricity, which is essential for mitigating climate change. Unlike fossil fuels, nuclear energy produces minimal greenhouse gas emissions, helping to reduce the overall carbon footprint of power generation. However, the main concern is the inevitable accumulation of nuclear waste, and this needs to be properly addressed. With the anticipated increase in the number of operating nuclear power plants around the world it is essential to develop new materials and technologies for nuclear waste management. In our latest study we have developed and tested new radiografted materials as potential 110mAg adsorbents. This silver radionuclide is a very elusive contaminant in the pressurized water reactors (PWR) and represents a major problem for normal operation. Additionally, 110mAg possess a significant danger to the environment, if not removed completely from the PWR wastewater.
Towards fast ptychography image reconstruction of EUV masks by deep neural networks
In this study, we explore and demonstrate a rapid method for actinic patterned EUV mask inspection based on a deep neural network (DNN) architecture which exploits a-priori information of the photomask sample. We aim to achieve fast, high-quality image reconstruction of an EUV mask by using comparatively few diffraction patterns in a formalism consistent with the ptychography approach.
We tested our prior-primed DNN method on both synthetic and experimental data, demonstrating that the sample can be reconstructed fast and with high fidelity, allowing us to map out the mask defects down to a size of about 40 nm.
Design and Preclinical Evaluation of a Novel Prostate-Specific Membrane Antigen Radioligand Modified with a Transthyretin Binder
Radioligands targeting the prostate-specific membrane antigen (PSMA) are currently used in the clinics to treat patients with metastatic castration-resistant prostate cancer. Continuous investigations are, nevertheless, conducted to design new small molecule-based radioligands and improve their respective pharmacokinetic properties. Various strategies have been devised to reasonably prolong the blood circulation, which would result into enhanced tumor accumulation and radiation dose delivered to eliminate the cancer cells. The goal of this study was to investigate the influence of the incorporation of a transthyretin binder (TB-01) in the tumor uptake of the resultant PSMA-targeted radioligand.